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Educate>RainWater Harvesting

Rainwater Harvesting

Rainwater harvesting is the accumulating and storing, of rainwater. It has been used to provide drinking water, water for livestock, and water for irrigation or to refill aquifers in a process called groundwater recharge. Rainwater collected from the roofs of houses, and local institutions, or from specially prepared areas of ground, can make an important contribution to drinking water. In some cases, rainwater may be the only available, or economical, water source. Many times water collection intiatives start with rainwater harvesting and the best management practices for storm water, ranging from rain barrels to ground catchments systems. Lafayette, Ross, and Wharton Elementary Schools in the School District of Lancaster have their own green initiative for rainwater harvesting.

 

 

 

Local Schools

The first school that I visited was Lafayette Elementary, located at 1000 Saint Joseph St in Lancaster, PA. Through research I found out that Lafayette Elementary was one of three Lancaster public schools that had a green roof installed this summer. The other two schools were Ross Elementary, located at 840 North Queen Street, and Wharton Elementary located at 705 North Mary Street. I took photos at Lafayette and Ross for my iMovie.

These vegetated roofs are designed to reduce rainwater runoff and conserve energy, and they are the first ever to be installed at public schools in Lancaster. The roofs were funded with a portion of a $479,000 energy harvesting grant that the planning commission received from the state Department of Environmental Protection. The School District of Lancaster received $118,710 for its two vegetated roofs at Lafayette and Wharton, each of which total 10,000 square feet. The district also received a $30,000 grant from the Lancaster Foundation for Educational Excellence for the 2,500-square-foot vegetated roof at Ross.

Since a vegetated roof weighs more than a regular roof it requires a little beefing-up to the structural support so it can handle up to 50 pounds per square foot of extra weight when wet.  Green roofs can last up to twice as long as a conventional design and they have multiple environmental benefits. Their extra insulating properties cut heating and cooling costs and reduce the heat island effect, the buildup of heat from vehicles, pavement and the flat black roofs common to urban areas.

The local green roofs will serve as an educational purpose as well, because Science teachers plan to integrate them into the classes as environmental science learning laboratories. One of the biggest down falls of the roofs is that it requires some initial weeding and will need to be watered during droughts lasting more than four weeks.

Other than that issue there is no need for any other maintenance. The roofs are planted with sedum, a hardy plant that goes dormant in the winter and rebounds in the spring. It also does not grow higher than a couple of inches, so there's no need for high-rise lawn mowing.

 

The roofs at Wharton and Ross include a layer of soil and crushed stone planted with sedum plugs grown by students at Lancaster County Career & Technology Center. At Lafayette, workers installed the sedum in rows of 4-inch-deep plastic trays measuring 1 by 2 feet. The trays allow the roots to poke out the sides but not the bottom, so they don't damage the roofs membrane. All three roofs are warranted against leaks for 20 years and equipped with electronic vector mapping, leak-detection systems that pinpoint problems.

The School District of Lancaster hopes to inspire others in the city to use green initiatives to reduce storm water runoff, which overtaxes the city's sewage treatment capabilities by more than 1 billion gallons a year. With these three roofs, Lancaster City now has almost one square foot of vegetated roof per resident, one of the highest per-capita rates in the country.

Roof rainwater can be of good quality and may not require treatment before consumption. Although some rooftop materials may produce rainwater that is harmful to human health, it can be useful in flushing toilets, washing clothes, watering the garden and washing cars; these uses alone are half the amount of water used by a typical home. Household rainfall catchment systems are appropriate in areas with an average rainfall greater than 7.9 inches per year, and no other accessible water sources.

lafross school
Photos by Thomas Wilmer

 

Chestnut Hill Cafe

After talking with Howard Jones, the Community Service Coordinator at Millersville University, he informed me that there was a public Rain Barrel at The Chest Nut Hill Café, located at 532 West Chestnut Street in Lancaster, PA. Howard and I got together and went to the Café and took some photos of the Rain Barrel, he was also with me when I went to the Elementary schools to take a look at their vegetated roofs. When we arrived at the Café we went inside and looked around and asked some questions, but didn’t really get any crucial feedback. The Rain Barrel was located on the outside of the building and had a lot of art work on it; you can see the photos in my iMovie.

chestnuthilldsrgs
Photos by Thomas Wilmer

 

Rain Barrels

A rain barrel is a tool that collects and stores rainwater from your roof that would be lost to runoff and to storm drains and streams. Usually a rain barrel is composed of a 55 gallon drum, a hose, PVC couplings, a screen grate to keep debris and insects out. A rain barrel is relatively simple and inexpensive to construct and can sit conveniently under any residential gutter down spout.

An advantage to having a rain barrel is that you can use the excess water for your lawn and garden, which can make up nearly 40% of total household water use during the summer. A rain barrel collects water and stores it for you when you need it most, like during a drought, watering plants, washing your car, or to top a swimming pool off. It provides an ample supply of free soft water to homeowners, containing no chlorine, lime or calcium making it ideal for gardens, flower pots, car and window washing.

  A rain barrel will save most homeowners about 1,300 gallons of water during the summer months. Saving water not only helps protect the environment, it saves you money, energy, and a decreased demand for treated tap water. Diverting water from storm drains also decreases the impact of runoff to streams. Therefore, a rain barrel is an easy free way for you to have a consistent supply of clean, fresh water for outdoor use.

  Ready-made rain barrels can be purchased from a number of companies, including hardware stores and garden supply stores. In addition, local governments sometimes offer them for a reduced price as part of their environmental education programs.

rain barrel
Photo by Thomas Wilmer

 

Engineers & Landscape Architects

When I went to Engineers and Landscape Architects (ELA), I had a meeting with Charles M. Hess, PE Director of Municipal Engineering at ELA. The interview went very well and I got a lot of information from him and his colleague. They were very friendly and seemed extremely interested with local initiatives with going green.
          
ELA are full-service Engineering and Landscape Architecture firm that concentrates on providing personalized, yet professional services to their clients from there Lititz and State College, Pennsylvania, offices. They ensure that their clients will have an outstanding experience when working with their staff on their projects. Their partners believe that in today's business environment; there is a direct correlation between employee ownership, client service and high client satisfaction.
           
 ELA Group was founded in 1996, and has provided Engineering and Landscape Architecture solutions for communities and their clients. ELA Group's corporate office is located in Lititz, a suburb of Lancaster, Pa, and the Central Pennsylvania office is located in State College, Pa. Their team includes registered landscape architects, project designers, registered engineers, project engineers, CADD technicians and administrative support staff.
 
ELA Group combines the artistic side of our nature through their landscape architecture staff, and the scientific side through their engineering staff. Their differences enable them to provide the best Landscape Architectural and Engineering consulting and construction administrative services for public and private sectors. ELA’s mission is to meet and exceed the diverse needs of their public and private clients by providing prompt, highly creative, technically skilled and high-quality design solutions. 

After talking with Mr. Hess and his colleague, I found out that rain barrels are a great tool to collect rainwater run-off. He also informed me that rain water harvesting is on a small scale compared to parts in California. Low shortage of water isn’t that big of a deal in this area of the country, but there are some people that want to make a change. He did inform me that the Amish are more accustom to rainwater harvesting than any one locally because of their beliefs. Mr. Hess actually just installed a rain barrel at his home and emailed me a few photos of it, which I used in my iMovie. He also gave me vital information on Live Green, Dr. Shirley Clark, and Innovative Wastewater Technologies

 

Live Green

LIVE GREEN is the only nonprofit environmental organization in Lancaster County that is focused on improving the environment in urban areas. Their mission is to build strong and healthy communities through environmental projects. They accomplish their mission by conveying key players from all three sectors (nonprofit, for-profit, and government) around key opportunities. They are particularly interested in working on projects that not only deliver positive environmental outcomes but also improve social and economic aspects of their communities. I actually called the organization and I spoke to Fritz Schroeder the Director of Programs at Live Green, and I asked him to tell me a little about the organization. After the brief interview, Mr. Schroeder sent me some photos of rain barrels around Lancaster and he sent me a Rain Barrel Registration and Assessment Form.

 In the past, LIVE GREEN was supported entirely by the Pennsylvania Department of Community and Economic Development (DCED). This funding is no longer available and, given the state’s budget crisis, they are working diligently to raise funds from private foundations, individuals, and direct income initiatives, such as workshops and rain barrel sales. They will greatly appreciate your financial support.

The LIVE GREEN’s Watershed Initiative has distributed more than 250 rain barrels to Lancaster residents since the spring of 2008. Collectively, these rain barrels divert more than 3 million gallons of rain water from over flooded storm sewer systems. The distribution of these rain barrels has been combined with hands-on workshops that educate citizens on the nature and impact of urban storm water pollution, and design solutions including rain gardens and bio-swales to compliment the installation of rain barrels.

They have also facilitated the installation of vegetated or green roofs on roughly 51,000 square feet of non-residential roof space in Lancaster City, in conjunction with the Lancaster County Planning Commission. Lancaster City is a competitor for the honor of having the most green roof area per capita of any city in the United States.

Lancaster City has a combined sewer system which transports not only rainwater, but also domestic sewage and industrial waste to the city’s single waste water treatment plant. During heavy rain events, when the waste water treatment plant exceeds capacity, the overflow of about 1 billion gallons of untreated water annually goes into the Conestoga River. The city’s green infrastructure plan addresses this problem in the most affordable and effective way.

According to LIVE GREEN rain barrels are available to the City of Lancaster residents at a subsidized cost through a grant with the Chesapeake Bay Commission.  We now have two easy ways for you to purchase rain barrels. Through its rain barrel program, Live Green facilitates educational seminars to engage residents about stormwater management alternatives, and green infrastructure improvements.

Rain barrels are one component of a green infrastructure approach’s to wet weather management that is cost effective and environmentally friendly. When used as a wet weather management technique, green infrastructure can reduce our reliance on traditional stormwater structures that are expensive to build, operate and maintain.

The primary goals of LIVE GREEN’s rain barrel program are to educate city residents about the nature of urban storm water pollution, and the causes and consequences. Second is to empower participants to take action and make a change by utilizing the green space around their home, like installing rain barrels, planting rain gardens, and planting native plants and trees. Lastly is to provide each member with an affordable high quality rain barrel, at a subsidized cost along with the training to prepare them to install and manage their rain barrels properly.
           
Rain barrels offer multiple impacts and benefits to both the homeowner and the municipality’s infrastructure. Using rain barrels helps to divert water from the municipal storm drain system. It also protects rivers and streams from runoff pollution. Rain barrels can control moisture levels around the foundation of your home and provide oxygenated, un-chlorinated water which is ideal for plants. The barrel can also direct overflow water to where it will have the most beneficial impact and conserve a vital natural resource.

 

Dr. Shirley Clark

Dr. Clark is the Associate/Assistant Professor of Environmental Engineering, at Penn State Harrisburg since 2003. Her goal is to impact of the engineered environment on nature and public health. Her research also focuses on the impact of stormwater runoff on the physical, chemical and biological quality of surface water bodies. Through teaching Dr. Clark hopes to instill an understanding of how people interact with the environment, particularly the water environment, and how their activities affect the environment.

            Here are some research projects from Dr. Clark:

  • Roofing Material as a Contributor to Urban Runoff Pollution

  • Infiltration vs. Surface-Water Discharge,

  • Green Roof Media Evaluation to Improve Pollutant Retention and Runoff Water Quality

  • Rainfall Energy for Erosion: Comparison of Map Values versus Calculated

  • Collection and Measurement of Stormwater Solids

  • Media Filtration for Urban Stormwater Treatment

  • Media Filtration for Urban Stormwater Treatment

            Here is a list of Dr. Clark’s teachings:

  • Hydrology- The study of the relationship between rainfall and runoff.

  • Hydraulic Design- The design of conveyance and collection systems.

  • Open-Channel Hydraulics- Open-channel flow and floodplain modeling. 

  • Risk Assessment- The risks of environmental chemicals and microorganisms.

  • Aquatic Chemistry- The study of chemical reactions in environmental waters. 

Her site control research has emphasized the importance of the selection of biorentation media for chemical pollutant removal and has emphasized the importance of the proper selection of roofing materials for controlling pollutant discharges from roofs. She is extending her roofing work to investigate the water quality of green roof discharge and the potential for capture and reuse of rainwater from both conventional and green roofing. She has published more than 75 major journal articles, conference papers, and reports on stormwater runoff treatment.

After reading the Pennsylvania Stormwater Best Management Practices Manual, I found out that there are twenty one Structural BMPs listed in the manual. I want to take the time to talk about a few of these BMPs, such as a Pervious Pavement with Infiltration Bed, an Infiltration Basin, Rain Garden / Bioretention, Rooftop Runoff – Capture & Reuse, Vegetated Roof.

 

Pennsylvania Storm Water Best Manegement Practice Manual

After reading the Pennsylvania Storm water Best Management Practices Manual, I found out that there are twenty one Structural BMPs listed in the manual. I want to take the time to talk about a few of these BMPs, such as:

  • Pervious Pavement with Infiltration Bed

  • Infiltration Basin

  • Rain Garden / Bioretention

  • Rooftop Runoff – Capture & Reuse

  • Vegetated Roof

 

Pervious Pavement

A pervious pavement consists of a permeable surface course underlain by a uniformly graded stone bed which provides temporary storage for peak rate control and promotes infiltration. The surface course may consist of porous asphalt, porous concrete, or various porous structural pavers laid on uncompacted soil.

The stormwater drains through the surface, and is temporarily held in the voids of the stone bed, and then slowly filtrates into the underlying, uncompacted soil. The stone bed can be designed with an overflow control structure so that during large storm events the peak rates are controlled, and at no time does the water level rise to the pavement level. A layer of nonwoven geotextile filter fabric separates the aggregate from the underlying soil, preventing the migration of particles into the bed. The bed bottoms should be level and uncompacted. If new material is required, it should consist of additional stone and not compacted soil.

Pervious pavements are well suited for parking lots, walking paths, sidewalks, playgrounds, plazas, tennis courts, and other similar uses. They can also be used in driveways if the homeowner is aware of the stormwater functions of the pavement. These roadways have been seen more in Europe, Japan, and in the U.S. In Japan and the U.S., the application of an open-graded asphalt pavement of 1inch or less on roadways has been used to provide lateral surface drainage and prevent hydroplaning, but these are applied over impervious pavements on compacted sub-grade soil. If properly installed and maintained pervious pavements has a significant life-span, and existing systems that are more than twenty years in age continue to function. This is so, because water drains through the surface course and into the subsurface bed, freeze-thaw cycles do not tend to adversely affect pervious pavement.

Pervious pavements are most susceptible to failure during construction, and therefore it is important that the construction be undertaken in such as way as to prevent. First is the compaction of underlying soil, second is contamination of the stone sub-base with sediment and particles. Third is the tracking of sediment onto the pavement and lastly is the drainage of sediment into laden waters onto a pervious surface or into a constructed bed.

Studies have shown that pervious systems have been very effective in reducing contaminants such as total suspended solids, metals, oil and grease. When designed, constructed, and maintained the right way by following guidelines, pervious pavement with underlying infiltration systems can dramatically reduce the rate and volume of runoff, and recharge the groundwater, and improve water quality. In northern climates, pervious pavements have less of a tendency to form black ice and often require less plowing. Sand and gravel should never be used on pervious pavements, although salt may be used on pervious asphalt, and commercial deicers may be used on pervious concrete. Pervious asphalt and concrete surfaces provide better traction for walking paths in rain or snow conditions.

The primary goal of pervious pavement maintenance is to prevent the pavement surface and/or underlying infiltration bed from being clogged with particle sediments.

To keep the system clean throughout the year and prolong its life span, the pavement surface should be vacuumed annually with a commercial cleaning unit. Pavements washing systems or compressed air units are not recommended. All inlet structures within or draining to the infiltration beds should also be cleaned out twice a year.

Potholes in pervious pavements are unlikely; though settling might occur if a soft spot in the sub-grade is not removed during construction. The added cost of a pervious pavement infiltration system lies in the underlying stone bed, which is generally deeper than a conventional sub-base and wrapped in geotextiles. Geotextiles are permeable fabrics which when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain.  However, this additional cost is often offset by the significant reduction in the required number of inlets and pipes.

 

Infiltration Basin

An Infiltration Basin is a shallow impoundment that stores and infiltrates runoff over uncompacted soils. The size and shape can vary from one large basin to multiple, and smaller basins throughout a site. Ideally, the basin should avoid disturbance of existing vegetation. If disturbance is unavoidable, replanting and landscaping may be necessary and should integrate the existing landscape as subtly as possible and compaction of the soil must be prevented.

The quality of the runoff is also improved by the natural cleansing processes of the existing soil layer and also by the vegetation planted in the basins. The key to promoting infiltration is to provide enough surface area for the volume of runoff to be absorbed within a given time of 72 hours or less. In case of an emergency an engineered overflow structure should be provided for the larger storms.

For existing areas that are not vegetated or for infiltration basins that require more digging, vegetation may be added. Planting in the infiltration area will improve water quality, encourage infiltration, and promote evapotranspiration. This vegetation may range from a meadow mix to more substantial woodland species. The planting plan should be sensitive to hydrologic variability anticipated in the basin, as well as to larger issues of native plants and habitat, aesthetics, and other planting objectives. The use of turf grass is discouraged due to soil compaction from the required frequent mowing and maintenance requirements.

  An Infiltration Basin can also be used for recreation in dry periods. Heavy machinery and vehicle traffic of any type should be avoided so it won’t compact the infiltration area. Another key to Infiltration Basins is that it can be incorporated into a new development. Existing vegetation can be preserved and utilized in the infiltration area. Runoff from adjacent buildings and impervious surfaces can be directed into this area, which will water the vegetation, thereby increasing evapotranspiration in addition to encouraging infiltration.

 

Rain Garden

A Rain Garden also known as a Bioretention, is an excavated shallow surface depression planted with specially selected native vegetation to treat and capture runoff. Bioretention is a method of treating storm water by pooling water on the surface and allowing filtering and settling of solids and sediments at the mulch layer, prior to entering the plant, soil, and pollutant removal. Rain Gardens are techniques that are used to accomplish water quality improvement and water quantity reduction.

Rain Gardens can be integrated into a site with a high degree of flexibility and can balance nicely with other structural management systems, including porous asphalt parking lots, infiltration trenches, as well as non-structural storm water BMPs. The Rain Garden vegetation serves to filter water quality and transpire water quantity runoff, and the root systems can enhance infiltration. The plants take up pollutants; the soil medium filters out pollutants and allows storage and infiltration of storm water runoff; and the bed provides additional volume control. Properly designed bioretention techniques mimic natural forest ecosystems through species diversity, density and distribution of vegetation, and the use of native species, resulting in a system that is resistant to insects, disease, pollution, and climatic stresses.

There are many different variations of Rain Garden systems; the most common one includes a gravel or sand bed underneath the planting bed. The original intent of this design, was to perform as a filter BMP utilizing an under drain and subsequent discharge. When a designer decides to use a gravel or sand bed for volume storage under the planting bed, then additional design elements and changes in the vegetation plantings should be provided.

rain garden
Photo by Thomas Wilmer

 

Rooftop Runoff- Capture & Reuse

Capture and Reuse includes a wide variety of water storage techniques designed to capture precipitation, hold it for a period of time, and reuse the water. Heavy rainfall may require slow release over time.

Cisterns, Rain Barrels, Vertical Storage, and similar devices have been used for centuries to capture storm water from the roofs of buildings, and in many parts of the world these systems serve as a primary water supply source. The reuse of storm water for potable needs is not advised without water treatment, although many homes in the U.S. were storing water in cisterns for reuse as little as a century ago. These systems can reduce potable water needs for uses such as irrigation and fire protection while also reducing storm water discharges.

Cisterns are a large, underground or surface containers designed to hold large volumes of water at least 500 gallons or more. Cisterns may be made out of fiberglass, concrete, plastic, brick or other materials. Vertical Storage are stand along towers, or fat downspouts that usually rest against a building performing the same capture, storage and release functions as cisterns and rain barrels. Storage beneath Structures may be incorporated into elements such as paths and walkways to supplement irrigation with the use of structural plastic storage units.

 

Vegetated Roof

An extensive vegetated roof cover is a thin covering of vegetation that is grown on and completely covers a conventional flat or pitched roof endowing the roof with hydrologic characteristics that more closely match surface vegetation than the roof. The overall thickness of the veneer may range from 2 to 6 inches and may contain multiple layers, consisting of waterproofing, synthetic insulation, non soil engineered growth media, fabrics, and synthetic components. Vegetated roof covers can be optimized to achieve water quantity and water quality benefits. Through the appropriate selection of materials, even thin vegetated covers can provide significant rainfall retention and detention functions.

Extensive vegetated roof covers are usually 6 inches or less in depth and are typically intended to achieve a specific environmental benefit, such as rainfall runoff mitigation. For this reason they are usually not irrigated, but some installations are open to public access, most extensive vegetated roof covers are for public viewing only. In order to make them practical for installation on conventional roof structures, lightweight materials are used in the preparation of most engineered media. Developments in the last 40 years that have made these systems viable include recognition of the value of vegetated covers in restoring near open-space hydrologic performance on impervious surfaces. Second, are advances in waterproofing materials and methods, and lastly is the development of a reliable moderate climate plant list that can thrive under the extreme growing conditions on a roof.

Vegetated roof covers that are 10 inches, or deeper, are referred to as intensive vegetated roof covers. These are more familiar in the United States and include many urban landscaped plazas. Intensive assemblies can also provide substantial environmental benefits, but are intended primarily to achieve aesthetic and architectural objectives. These types of systems are considered roof gardens and are not to be confused with the simple general design.

Most extensive vegetated roof covers fall into three categories and they are single media with synthetic under-drain layer, dual media, and dual media with synthetic retention/detention layer. All vegetated roof covers will require a premium waterproofing system. Depending on the waterproofing materials selected, a supplemental root-fast layer may be required to protect the primary waterproofing membrane from plant roots.

vegetated garden
Photo by Thomas Wilmer

 

Innovative Wastewater Technologies

The intent for these technologies is to reduce the generation of wastewater and potable water demand while increasing the local aquifer recharge. Potable water is fit for consumption by humans and other animals. It is also called drinking water, in a reference to its intended use. Water may be naturally potable, but it may need to be treated in order to be safe. In either instance, the safety of water is assessed with tests which look for potentially harmful contaminants.

The key requirement is to reduce the use of municipally provided potable water for building sewage conveyance by a minimum of 50%, or treat 100% of wastewater on site to tertiary standard.

Conventional wastewater systems require significant volumes of potable water to convey waste to municipal wastewater treatment facilities. Once wastewater has been conveyed to treatment facilities, extensive treatment is required to remove contaminants before discharging to a receiving water body. A more efficient method for handling wastewater is to treat it on-site. On-site wastewater treatment systems are responsible for transforming supposed waste into resources that can be used on the building site. These resources include treated water volumes for potable and non-potable use, as well as nutrients that can be applied to the site to improve soil conditions. Reducing wastewater treatment at local treatment facilities minimizes public infrastructure, energy use and chemical use.

Facilities that generate large amounts of wastewater can realize considerable savings by recycling graywater that can be effectively treated and reused. For instance, carwashes generate large volumes of graywater that can be effectively treated and reused. Since a separate tank, filter and special emitters are necessary for a graywater irrigation system, dual plumbing lines are installed during construction and the cost of plumbing will approximately double.

Water recovery systems are most cost-effective in areas where there is no municipal water supply, where the developed wells are unreliable, or if well water requires treatment. Collecting and using rainwater or other site water volumes minimizes the need for utility-provided was, therefore reducing some initial and operating costs. Both wastewater treatment systems and water recovery systems include an initial capital investment plus the maintenance requirements over the building’s lifetime. These costs have to balance with the savings in water and sewer bills. Currently, packaged biological wastewater systems have an initial high cost relative to the overall building cost due to the novelty of the technology.

Strategies

Develop a wastewater inventory and determine areas where graywater can be used for functions that are normally served by potable water. These functions could include sinks, showers, toilets, landscape irrigation, industrial applications and custodial applications. Potable water is used for many functions that do not require high- quality water. Graywater systems reuse the wastewater from sinks, showers and other sources. Roof water or ground water collection systems harvest water that otherwise would be absorbed into the ground or released to local water bodies.


This site was created by Thomas Wilmer at Millersville University of Pennsylvania

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